Write large binary file in C

Question

I'm using 64bit mingw to compile c code on windows x64. I'm using fwrite to create binary files from memory array. I want to write ~20Gb calling this function but it just write until 1.4~1.5gb and then it stops writting (without crashing, just hangs there.... doing nothing). Is there any solution? Right now I'm writing 20 files and then I merge them. Opening the file as 'ab' works but I cant read the file properly if I use that mode.

Sample (pseudo)code:

    short* dst= malloc(20GB);
    *calculations to fill dst* 
    file=fopen("myfile",'wb');
    fwrite(dst, sizeof(short), 20GB/sizeof(short), file);
    fclose(file)

That program never ends and file size is never grater than 1.5GB

Answer 1

Write it in smaller chunks. For heaven's sake, don't try to malloc 20gb.

Answer 2

Depending on the environment (operating system, memory model, file system), it might not be possible to create a file greater than 2 GB. This is especially true with MSDOS file systems and of course could be true on any file system if there is insufficient disk space or allocation quota.

If you show your code, we could see if there is any intrinsic flaw in the algorithm and suggest alternatives.